1. Field of the Invention
This invention relates to the mass of undifferentiated cells termed callus of the vanilla-producing orchid Vanilla planifolia and has as its principal object provision of a reliable method for producing the same. It also provides utilities of the callus as a source for regenerating the orchids and as a source of vanillin.
2. Prior Art
Vanilla planifolia, a monopodial orchid usually propagated by cuttings, is the natural source of vanilla flavoring.
Recently, two tissue culture methods of propagation of this orchid have been reported using (1) nodal segments (Cervera et al. (1981) In vitro propagation of vanilla (Vanilla planifolia A.) Environ. Expt. Bot. 21:441 (Abst.); Kononowicz et al. (1984) In vitro propagation of Vanilla planifolia. Hortscience 19:58-59) or (2) aerial root tips (Philip et al. (1986) Clonal propagation of Vanilla planifolia (Salisb.) Ames using tissue culture. J. Plant Physiol. 122:211-215).
The status of callus of the orchid is somewhat obscure. Unsuccessful attempts to induce formation of the callus have been reported (Kononowicz et al., op. cit.). Other investigators mention callus: see Sahai et al., Producing high value food ingredients via plant biotechnology, The World Biotech Report 1980, Vol. 2, Part 1, pp. 71-85. Jarret et al., (1984) Shoot-Tip Vanilla Culture for Storage and Exchange, Plant Genetic Resources Newsletter 57:25-27, note the formation of callus without giving any properties. At any rate, there has heretofore been no reliable method of producing callus.